Open end wrench with escapement



March 5, 1963 R. A. M'. VANTCHOURA 3,079,820

OPEN END WRENCH WITH ESCAPEMENT Filed Aug. 2, 1960 2 Sheets-Sheet 1 Fig. 11

March 5, 1963 R. A. M. VANTCHOURA 3,079,820

OPEN END WRENCH WITH ESCAPEMENT Filed Aug. 2, 1960 2 Sheets-Sheet 2 Fig.7

3,il79,82tl @PEN END WRENQH WEE H ESCAPEWNT Raymond Andre Marcel Vantchoura, Asnieres, France,

assignor, by mesne assignments, to Inventions Finance Corporation, a corporation of Delaware Filed Aug. 2, 1966, Ser. No. 47,652 Claims priority, application France Aug. 4, 1959 7 Claims. (Cl. 81-179) The present invention relates to an open end wrench with escapement and more particularly to a ratchet wrench of the general type in which one of the jaws carries a slider so located and shaped as to provide an improved operation of the said wrench.

Prior devices of this general type suffered from many defects, and difficulties have arisen from different conditions to be fulfilled by such devices, namely for driving the screw a firm grip must be achieved whereas the sliding motion of the slider should be easy at the time of the return motion of the wrench.

An object of the present invention is therefore to overcome the above mentioned drawbacks while providing other advantages which will appear from the description.

Another object of the present invention is to provide an open end ratchet wrench in which the planes of the operating surfaces of the jaws are inclined in such a way as to facilitate the operation of the wrench.

Still another object of the invention resides in providing one of the jaws of such a wrench with a slider of improved construction.

Yet another object of the invention is to adapt it to wrenches of the adjustable jaw type.

According to a feature of the present invention, there is provided an open end wrench of the above mentioned type, in which the operating surfaces of the jaws are inclined so as to form an angle 20: such that tangent a is smaller than the smallest friction coefiicient likely to exist between the slider, the screw and the jaws of the wrench during use.

Another feature of the invention resides in choosing the point of contact of the slider carried by one of the jaws of the wrench with the screw, when the latter is fully engaged between said jaws, so that said point of contact is located on the opposite side of the apex of the said angle 2a between the operating surfaces of said jaws with respect to a perpendicular line to the operating surface of said jaw carrying the slider and passing through the apex of two sides of the screw about which takes place the initial rotary movement of said open end wrench during the escapement process.

A feature of the invention resides yet in the shape given to the slider, which comprises a semi-cylindrical portion terminated by an inclined plane section.

Other and further objects, features and advantages of the invention will become apparent as the description of preferred embodiments thereof proceeds.

FIGURE 1 represents one end of a screw spanner incorporating features of the present invention.

FIGURE 2 represents a cross-section along the line XX of FIGURE 1.

FIGURE 3 represents a position of the screw in the screw spanner during escapement.

FIGURE 4 represents another position of the screw in the device of FIGURE 1 in which escapement is impossible.

amass Patented Mar. 5, 1953 FIGURES 7 to 12 represent various alternative embodiments of the invention.

As briefly explained above, the driving movement imparted to the screw by the wrench cannot be considered as satisfactory unless there is no sliding of the slider.

If 20: is the value of the angle between the operating surfaces of the jaws and if f is the value of the friction coefiicient between the slider and the jaw carrying it and between the slider and the screw (assuming the friction coefiicient being the same in both cases), calculus and experiment show that there will be no sliding only if thus giving a rule for avoiding sliding: (tan u f).

This condition is contradictory to the conditions to be fulfilled for the escapement of the screw.

The initial return movement of the Wrench corresponds to the driving motion in a wedge mechanism (as a freewheel device for instance) and in such a mechanism there is a driving motion and not an escapement when tan tx It will be seen hereinafter how to avoid this drawback.

The open wrench represented in FIGURE 1 comprises a handle 1, a jaw 2 integral with the handle 1, said jaw comprising two plane surfaces 3, 4 placed at an angle of and a jaw 5 also integral with the handle 1 and carrying a slidable member 6 adapted to slide over said jaw 5.

The slidable arrangement of the slider 6 and the jaw 5 may be of the same type as the slidable arrangements generally used for the sliding of the movable jaws in adjustable wrenches. The slider 6 comprises (see FIGS. 1 and 2) a flattened portion 7 and a cylindrical portion 8 whose generatrix is parallel to the displacement of the slider and which is displaceable in a groove of corresponding shape '7, 8' provided in the jaw 5.

The lower part of 9 of the slider normally rests upon the face it} of the jaw 5, the parts 7 and 8 being solely used for guidance and not withstanding any effort. The face 10 of jaw 5 is at an angle 20: (FIG. 1) with face 3 of jaw 2. A pin 11 is placed in the jaw 5 to limit the right hand displacement of the sliding member as seen in FIGURE 1. A traction spring 12 is provided in a hole 13 provi ed in the cylindrical portion 8 of the slider. This spring is fixed by one of its extremities to the pin 11 and the other extremity is fixed on a pin 14 fixed in 8. The slider 6 may be displaced in the left hand direction as seen in FIGURE 1 against the action of the spring 12. Normally the slider 6 butts against the pin 11.

The operation of the device is as follows:

Considering the line NN perpendicular both to the outside surface of the slider 6 and to the face 3 of the jaw 2, it will be seen that point N divides the outside surface of the slider 6 into two parts, one part 15 located on the left of point N (FIG. 1), the cross section of which being circular with a radius R and the center being located on line N the part located on the right hand side of point N comprises a circular portion 16 having a radius r and a center also on the line NN and a rectilinear portion 17. The length of the common perpendicular line NN' is slightly greater than the dimensions of the screw for which the wrench is designed.

There is shown in FIGURE 1 in dash and dot line a hexagonal screw, apices of which are indicated at A, B, C, D, and E.

The line EH is a line passing from the apex E of the screw perpendicular to the face 10 of the jaw 5; this line EH reaches at point G the face AB of the screw.

The faces CD, DB of the screw are in contact with the operating surfaces 4 and 3 of the wrench and the slider rests against the pin 11, the line NN' reaches the face AB 3 of the screw at a point I which is located between apex A and point G.

, Anaspect of the present invention resides in providing the shape and the position of the slider so that point I is suitably located with respect to points A, B and G.

. At the start of the driving movement in the direction of arrow F the portion 15 of the slider whose radius is R comes into contact with the face AB of the screw.

As stated above, to avoid any sliding during driving of the screw it is necessary to select the angle 2m so that tangent a is smaller than the smallest friction coefiicient which is likely to be found, due account being taken of the fact that the wrench may be used in greasy conditions; however taking this into account, it is necessary that the angle 20: be large enough to facilitate the escapement.

Experiments have taught that a good value for the angle 21 is and that in some cases 12 may be used but this seems a'value that ought-not be exceeded.

Besides, it is advisable that the radius of curvature of the surface 15 of the slider which comes into contact with the screw at the moment of driving, be as small as possible; the value of R is chosen just ,sufiicient to prevent the stresses, caused by the slider on the screw during driving, from damaging the screw.

With respect to the return movement of the screw, in direction F FIGURE 3 (escapement), this is mainly a position with respect to the screw, that is to say where there exists a slight play between face CD of the screw and face 4 of the wrench.

According to the invention, it is necessary to provide that point I be located between point (3 and the apex A, as close as possible to point A but with a sufficient guarding distance from this point.

For small screws, the guarding distance will be relatively more important than for large screws and the point I will be close to point G. For large screws, point I may be closer to point A and the escapement will be thereby improved.

rotary motion of the wrench about the apex E of the screw (FIG. 1) and this initial movement is impossible or very difficult to achieve if certain conditions are not fulfilled.

This initial movement of the escapement is analogous to What has been described above with respect to the driving movement of a wedge mechanism (as used in a free wheel device for instance) in which the angle of the tangents to the wedging body is with the condition tan oz f, being the friction coefiicient.

If the point of contact of the slider with the screw at the moment of the escapement is located between point G (crossing point between the face AB of the screw with the perpendicular line on face AB passing through apex E), and the apex B, the escapement is theoretically impossible; the slider is wedged and cannot slide either on face 10 of the jaw or on face AB of the screw.

The escapem ent is theorically possible only if the point of contact ofthe slider with the screw is located between point G and the apex A, and then it is all the more easy if the point of contact is closer to apex A.

it is therefore advisable to determine the position of the slider so that point I be located between point G and point A, that is to say so that point I be located, with respect to the perpendicular line EH, on the side opposed to the apex of the angle 20: existing between the operating faces 3 and 10 of the jaws of the wrench.

The invention provides further for giving to the surface 16v of the slider, which surface comes into contact with face AB of the screw during the return movement of the wrench, a radius of curvature r as small as possible, and which in some cases may be equal to zero.

By means in part of this arrangement, the slightest play between the dimensions of the screw and the opening of the jaws substantially increases the value of the angle of the face AB of the screw with respect to the face 10 of the jaw, thus facilitating the escapement and the more so as the point of contact lies closer to point A. However, in some cases, in particular when radius R is small, it is possible to render machining more easy, by selecting r=R.

The truncation made by the plane surface 17 is of a very great interest. On the one hand it facilitates per se the movement of escapement, and on the other hand it enables a reduction of the distance travelled by the slider both during the escapement period as well as during the return movement of the slider towards its driving position; this distance is the shorter as point I is closer to point A.

'If' point I is close to point A, the ratchet action is still possible when the wrench is not quite in a correct In the embodiment represented in FIGURE 1, the return movement of the wrench takes place without having to take special measures for the handling of the wrench; as soon as the escapemen-t is started, the face 3 slides over the apex E (FIG. 3), the face 4 comes again into contact with the apex D and slides over it, and the slider automatically slides without stress over the screw while remaining in contact with it; there is a permanent contact between the faces 3 and 4 of the wrench and of the slider with the screw; when a sixth of a revolution has been made, the wrench is again in a position for a further drive without having to perform a further return motion in order that the slider may assume a correct position for the driving.

If desired, it is possible to use an open end wrench with an escapement, such as the one shown in FIGURE 1, as an ordinary wrench, that is to say by rendering impossible the escapement action.

It is sufficient to displace the wrench with respect to the screw by leaving a space between the face CD of the screw and the face 4 of the wrench, in order that point I will be located between point G and the apex B, as is shown in FIGURE 4. The initial return movement of the wrench-a rotation about apex E-in the direction of arrow B; is then impossible, the present invention providing tan a f, the escapement is impossible and the wrench may then 0 erate exactly as an ordinary flat wrench in both directions of rotation.

However, if one wishes to use frequently and for heavy Work, the wrenches in accordance with the present invention, both as an escapement wrench and as an ordin-ary wrench (for a particular position of the screw with respect to the wrench), it is then advisable to reduce the value of the angle 2a and to let this angle assume values between 6 and 8 or close thereto. It is also advisable to increase slightly the length of the jaw 2.

It is also possible to provide on jaw 2 a device which imposes such a position to the screw with respect to the wrench, that it is possible to employ the wrench with positive driving in both directions; and the said device disappears into the jaw when it is desired to use the wrench with the escapement feature.

If, on the contrary, it is desired that positive driving in the direction of arrow F (FIG. 4) can never take place, it is sufficient for this purpose to limit the length of the face 3 of the jaw 2 and to choose this length equal to DE, the length of one face of the screw. The initial escapement movement is then always possible, Whatever may be the position of the screw with respect to the wrench, if the initial position of point I is suitably determined.

FIGURE 5 represents an embodiment of the invention as shown in FIGURE 1 in the case of a wrench with adjustable jaws.

The description given in connection with the arrangement shown in FEGURE l, in particular with respeotto the position and to the shape or" the slider, is applicable to the arrangement represented in FiGURE 5, which is similar to the one shown in FIGURE 1. The only difference is that the jaw 5 which was integral with handle 1 has been transformed into a mobile or adjustable jaw 5b. The connection between the adjustable jaw 51: and

the handle 1b may be realised according to any known way.

In the case of FIGURE 5, it is important to determine correctly the extent of the displacement of the adjustable aw.

It is possible to determine point-s I and I corresponding to the biggest and smallest screw for which the wrench is designed, by providing a guarding distance I A relatively greater than the distance I A and providing the base plane 18 parallel to I; D.

In the case of FIGURES 1 to 5 the slider with the escapernent device moves towards the outside of the wrench and such a slider may be termed an outside slider. The slider may be carried by the upper jaw; it moves then towards the interior of the wrench and it may be termed an inside slider.

FIGURE 6 represents an embodiment of an inside slider with an adjustable wrench of the rack type. The face 100 of the jaw on which slides the slider 60 is perpendicular to the direction of the displacement of the adjustable jaw 2c.

The adjustable jaw 2c moves in accordance with a translation movement along the handle 1c and this jaw comprises two operating surfaces 3c and 4c, the planes of which form an angle of 120 thus determining the position of the screw. The surface 30 is placed at an angle 20: with regard to the surface lilo. The points G and I such as defined above are the same for any type of screws.

What has been described above respecting the position of the slider and its configuration applies to the present embodiment. By way of example, there is represented a slider in which the rounded portion 16 (of FIG. 1) has a radius equal to zero: the straight portion 17 of the slider starts directly from the foot N of the common perpendicular line.

It would also be possible to employ a slider of the so-called inside slider type in the wrenches shown in FIGURES l and 5. However in the case of a wrench with fixed opening (FIG. 1) for equal strength, the wrench is less bulky with a slider of the so-called outside slider type and also more easy to handle.

In the case of a wrench of the adjustable jaw type, the inside slider would be mounted on a jaw integral with the handle whereas the outside slider would be mounted on the adjustable jaw 5b which operates far better and is more easy to machine.

The invention is independent of the way in which the sliding connection of the slider with the jaw carrying it is made.

The invention is also independent of the way in which the restoration of the spring is achieved. Use may be made of traction springs or of compression springs, wire springs or blade springs, etc. and in some cases use may be made of an elastic substance, such as rubber for instance.

There is shown by way of example in FIGURES 7 to 12 various ways of connecting a slider with a wrench as well as various means for restoring the slider into its rest position; any way of connecting the slider to the key may be associated, in general, with any means for restoring the slider.

In FIGURES 7 and 8, the jaw 5d comprises a thinned down portion 19 and two grooves 20, 21 parallel to the face 153d. The slider 6d comprises two jaws 22, 23 provided with bosses 24, 25 adapted to slide in the grooves 21?, 21.

The restoring of the slider is provided by a blade spring 26 fixed in 27 on the jaw, and this spring passes through the slot 28 provided in the jaw.

In FIGURES 9, 10, 11, the spring is used both as a restoring means and as a means for securing the slider. In this example, the slider 6 comprises a flat tail 29 which may be adapted to slide in a slot 39 of the jaw 5.

In the jaw 5 and parallel to its face 10 is pierced a hole 31, overlapping the slot 30, and the diameter of this hole is slightly greater than the width of the slot 30. This hole is used for housing and guiding a spring 32 which in FIGURE 9 is a compression spring.

The tail 29 of the slider may be thin since it has to withstand no effort; the slot 30 may thus be very narrow and the hole 31 may be of a small diameter. The total thickness of the jaw 5 may therefore be relatively small for a high strength.

The tail 29 of the slider comprises an elongated opening 33 the width of which is substantially equal to the diameter of the hole 31, and it is used also as a housing and a guide for the spring 32 in such a way that the slider is connected to the key by means of spring 32.

A pin 34, integral with the jaw 5 and which passes through the opening 33 of the slider is used both as an abutment for the slider and as a resting point for the spring 32.

In the embodiment of FIGURE 9, the cross-section of the surface of the slider in contact with the screw comprises only a single radius of curvature, as the choice r==R has been made; the cross-section is a portion of a circle 15 the center of which is located on the face 10, the straight portion being truncated by a plane 17 which has, as indicated above, two important functions, namely to facilitate the escapement movement and to reduce the distance travelled by the slider.

In FIGURE 12, the connection between the slider and the wrench is provided by two pins 3536 integral with the jaw 5, whereas the fiat tail 29 of the slider comprises two slots 3738 which surround the said two pins.

The pins are used also as abutments for the slider. The restoration of the slider is provided by a wire spring 39 which coils about a pin 40 and rests against the jaw 5.

The invention is not limited to the embodiments described but encompasses every alternative falling within the claim scope.

All the arrangements described for fixed opening wrenches apply also to wrenches with adjustable openings.

What I claim is:

1. An open end ratchet wrench for polygonal fasteners comprising a pair of spaced apart jaws having their major faces slightly inclined to one another, a ratchet slider secured for limited sliding motion along a major face of one of said jaws, and means biasing said slider in the direction towards the apex of the divergence angle between said major faces; said angle being such that the tangent of half of said angle is less than the effective coefficient of friction between said slider and said one jaw, and said slider having its distal surface profiled to engage one polygonal edge of a fastener at a point between the proximate corner thereof and the point of intersection of that face with a line perpendicular to said one major face and passing through the corresponding corner of the opposite edge of the fastener when the latter is seated upon the major face of the other jaw.

2. A wrench in accordance with claim 1, in which the divergence angle between said major faces is approximately 10 degrees.

3. A wrench in accordance with claim 1, in which the said distal surface of the slider has an arcuate profile in, the region in which it engages the fastener.

4. A wrench in accordance with claim 1, in which the said distal surface of the slider has an arcuate profile in the region in which it engages the fastener, and a chamfered profile merging from said arcuate profile in the direction lying towards the apex of the divergence angle.

5. A wrench in accordance with claim 1, in which said slider has a portion rabbeted into the face of said one aw.

6. A wrench in accordance with claim 5, in which said biasing means comprises a coil spring connected to said slider and to said one jaw.

7. A wrench in accordance with claim 1, and adjustabl'e means for varying the distance of separation of said two jaws.

References Cited in the file of this patent UNITED STATES PATENTS 8 Brins July 29, 1924 Parker Feb. 21, 1933 Yavner July 28, 1953 Grinnell Q May 17, 1955 V Crittenden Ian. 10, 1-956 'Blosdell June 11, 1957 Wheeler Nov. 15, 1968 

1. AN OPEN END RATCHET WRENCH FOR POLYGONAL FASTENERS COMPRISING A PAIR OF SPACED APART JAWS HAVING THEIR MAJOR FACES SLIGHTLY INCLINED TO ONE ANOTHER, A RATCHET SLIDER SECURED FOR LIMITED SLIDING MOTION ALONG A MAJOR FACE OF ONE OF SAID JAWS, AND MEANS BIASING SAID SLIDER IN THE DIRECTION TOWARDS THE APEX OF THE DIVERGENCE ANGLE BETWEEN SAID MAJOR FACES; SAID ANGLE BEING SUCH THAT THE TANGENT OF HALF OF SAID ANGLE IS LESS THAN THE EFFECTIVE COEFFICIENT OF FRICTION BETWEEN SAID SLIDER AND SAID ONE JAW, AND SAID SLIDER HAVING ITS DISTAL SURFACE PROFILED TO ENGAGE ONE POLYGONAL EDGE OF A FASTENER AT A POINT BETWEEN THE PROXIMATE CORNER THEREOF AND THE POINT OF INTERSECTION OF THAT FACE WITH A LINE PERPENDICULAR TO SAID ONE MAJOR FACE AND PASSING THROUGH THE CORRESPONDING CORNER OF THE OPPOSITE EDGE OF THE FASTENER WHEN THE LATTER IS SEATED UPON THE MAJOR FACE OF THE OTHER JAW. 